Huh ... I rather enjoyed the film.
I think for me, what seemed like irrational survival decisions to you were the obvious things people would do because they want to live a life as much as possible. Think of lockdown during the pandemic and how much people just wanted to "get back to normal". I think people doing risky things at least some of the time while thinking that it will be totally fine is actually a very realistic take on a post-apocalyptic survival story especially with its timeline being a long one as is the case in A Quiet Place.
Convincing yourself that you can totally get away with something is a way of convincing yourself that things are actually OK, even they are not at all.